Hi I am having a problem getting shadows to render as a seperate pass with final gathering. I can see them on a lambert surface but they don't seem to render out on a Use Background Shader or even as a seperate pass in a batch render. Gunna have to composite this somehow..

any ideas?

anthonymcgrath

08 August 2004, 04:37 PM

Yeah I had this problem last night actually :D I was using a hdr map on an environment sphere to light the model and I had one light in the scene that casted my primary shadows on the floor from my car model. The problem was to get the shadows I had to turn the light intensity up to a value of 1 which was bleaching the lighting with the hdr final gather illumination too. I turned the lighting down to 0.01 and it made the lighting great but I lost the shadows. To get around it in the same renderpass I opened the shadow colour in the spotlights attr editor and set it to a value below 0 to -0.3 or something with raytraced shadows. This seemed to bring them back into the scene.

sorry - I know thats a long winded explanation but there yer go - simply set the shadow colour of the shadow casting light to a minus value :D

ant
waffler
newc
uk

MunCHeR

08 August 2004, 04:46 PM

One other trick I was told was to set your light to an intensity of 1.0, duplicate it and set the duplicate to -1.0 and enable shadows on one of those lights, so the light intensities cancel each other out so you fet your nice final gather lighting and some sexy raytraced shadows. Probably other ways but thats what a buddy told me and from memory it qorks quite well.Let us knbow how you get on:thumbsup:

MunCH

PS: apologies if this is totally irrelevant to your question, but you never know what might help :D

anthonymcgrath

08 August 2004, 08:51 AM

whoa didn't know you could do that muncher. Have to give that a shot and see what happens. The only problem I found with my method is that I cant seem to tinge the shadow colour with some blue or another colour as I'm only setting one value to a minus figure. I can probably do it with the lights colour but I'm def gonna have to give that two lights method a shot

BillSpradlin

08 August 2004, 09:12 AM

Yea I use that technique quite a bit, Ed Harris turned me on to that trick, comes in very handy.

TomD

08 August 2004, 09:39 AM

here is a nice thread about Final Gather and shadow passes

http://www.cgtalk.com/showthread.php?t=118924

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